Manufacture of artificial silk



"Patented Apr. 27, 1e26.

UNITED STATES PATENT OFFICE.-

DA'vm GERARD zw n'rz, or Annn'nnr, NETHERLANDS, ASSIGNOR TO N AmLoozE VENNOOTSCHAP NEDEBLANDSCHE K UNSTZIJ'DEFABRIK, OF A RNHEM, NETHER- LANDS.

2K0 Drawing. I

To all whom it may concern:

Be it known that I, DAVID GERARD ZWARTZ, a "subject of .the Queen of the Netherlands, residing at Arnhem, in the 5 Province of Guelderland, the Netherlands,

haveinvented certain new and useful Improvements in the Manufacture of Artificial" Silk, of which the following is a specification.

The speed of manufacture of artificial silk in a factory producing threads of different denier is impaired .by the difiiculty of distinguishing the different deniers. After the bleaching and other after-treatments the threads are in the form of skeins which may easily be classed*by attaching to them coloured strings. 3 Before a thethreads have arrived at the form of skeins, however, their differentiation is far from easy.

For example, the artificial silk threads of 80 denier wound on bobbins are washed in the usual way, and a quantity of methylene blue is added to the last quantity of the Washing liquid. 'The artificial silk is dyed blue and keeps this colour during the fol- 40 lowing treatments, till the bleaching removes the' colour from the threads. For threads of 100 denier the same operation is performed with and dye, and

so on.

My'invention relates to an improvement MANUFAGTUBE or AnrmIcrAI. srmn Instead of dyes which are decolorized easily by the bleaching liquid, dyes may be used which are removed or decolorize by the action of one of the other after-treatv ment baths.

My invention may also be applied in the ized condition in the spinning centrifuge, or in some other way.

- ltgy-invention is particularly applicable in the viscose .silk vmanufacture, without any difliculty or unfavourable effect arising therefrom. But also in the manufacture of artificial silk by the cuprammonium and nitrocellulose processes, my invention is of considerable importance.

It is' also possible to add the dye in a separate bath, immediately after spinning, or. on completion ofthe washing. Preferably a dye is used which-is completely decolorized by the bleaching liquid. However, dyes may be used which are removed by simple washingwith alkaline or acid liquids V or even with ure water. In the latter case, the dye and e added only after the washing process has been completed.

I claim:

1. The improvement in .the' manufacture of artificial silk which consists in facilitating the keeping apart of threads of different denier by wholly or in part dyeing the artificial silk durin or after the spinning with a dye which is ecolorized or removed com- 2 letely or substantially completely by thev leaching process or any other after-treatment.

2. q The mode of applying the improvement referred to in claim 1 which consists in adding the dye to the washing liquid at the end of the, washing;

In testimony whereof I aflix my signature.

1). G, ZWARTZ. 

